Ceph backup

Hi,
I am experiencing slow backup speed when I backup ceph images in proxmox. I do not see any problems with network and ceph. I would like to know what type of ceph functionailty is used by proxmox to do backups ? ceph export ? I would like to debug ceph, but I do not know how proxmox does backups in ceph. Now backups are sth around 40MB/s and it should be much faster. I did test backups from ceph to local storage.

UPDATE:
I did small test:
standard proxmox backup took ~4 minutes
using rbd export and lzop was around ~1 min

However, I am not sure if these equals also I do not know if export is correct way to do live backup.

Staff Member

I am experiencing slow backup speed when I backup ceph images in proxmox. I do not see any problems with network and ceph. I would like to know what type of ceph functionailty is used by proxmox to do backups ? ceph export ? I would like to debug ceph, but I do not know how proxmox does backups in ceph. Now backups are sth around 40MB/s and it should be much faster. I did test backups from ceph to local storage.

maybe itd be worth it to collaborate with the Ceph guys on this. Especially since theres another issue involving backups to be solved (by the Ceph guys): cache pools. More to the point: if you have a cache pool in front of your Ceph storage and you take a backup, you essentially clear out the entire cache (that used to contain most commonly used objects) by replacing it with the backup. As such a specific read method for backups would be desirable, that would a) read in bigger blocksizes (4M preferrably) and b) "bypass" the cache for such a backup process. This last bit would have to make sure the data is consistent:

Backups in general are sadly really more of an afterthought for Ceph, as backing up Petabytes of data simply isnt desirable and in the end thats the amount of data Ceph has been designed around. Of course there are also much smaller setups (like the ones that would be sufficient to 'normal' datacenter virtualization) where backups ARE feasible. This is an area where Ceph could still improve quite a bit.

maybe itd be worth it to collaborate with the Ceph guys on this. Especially since theres another issue involving backups to be solved (by the Ceph guys): cache pools. More to the point: if you have a cache pool in front of your Ceph storage and you take a backup, you essentially clear out the entire cache (that used to contain most commonly used objects) by replacing it with the backup. As such a specific read method for backups would be desirable, that would a) read in bigger blocksizes (4M preferrably) and b) "bypass" the cache for such a backup process. This last bit would have to make sure the data is consistent:

Backups in general are sadly really more of an afterthought for Ceph, as backing up Petabytes of data simply isnt desirable and in the end thats the amount of data Ceph has been designed around. Of course there are also much smaller setups (like the ones that would be sufficient to 'normal' datacenter virtualization) where backups ARE feasible. This is an area where Ceph could still improve quite a bit.

Hi,
is here anything new in this area? My backups run around 30MB/s from ceph storage but more than 100mb/s from nfs based storage to the same location. Rados bench shows read around 300mb/s. It is quite unconvenient.
Isn`t here any settings or anything else I can do to improve performance? I have found nothing regarding this matter on google as well.

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